Faculty Science and Forestry
QUANTITATIVE ANALYSIS OF THE IMPACT OF AGRICULTURAL
INTENSIFICATION ON SOIL FERTILITY IN ARABLE LANDS, GHANA
Yaa Pokuaa
MASTER’S THESIS
BIO-ECONOMY AND NATURAL RESOURCE MANAGEMENT (ECORES)
JOENSUU 2016
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Pokuaa, Yaa. 2016. Quantitative analysis of the impact of agricultural intensification on soil
fertility in arable lands, Ghana. University of Eastern Finland, Faculty of Science and Forestry
and CSIR-FORIG/UEF Graduate School, Master’s Thesis in Bio-Economy and Natural
Resources Management (ECORES), 55p.
ABSTRACT
The study examined the impact of agricultural intensification on soil fertility in arable lands
within five farming districts in the Ashanti Region Ghana. The study is based on the premise that
the current agricultural intensification practices have not contributed to increased productivity
but instead, have impacted cultivated lands negatively.
Two hundred farmers were selected
randomly from the five districts within Ashanti Region. A questionnaire was developed based on
the objectives of the study to collect data on farmers land use activities, production cost and their
perceptions of the challenges facing agricultural intensification. Soil testing was undertaken to
determine the soil fertility status of fields under intensified systems using non-intensified fields
in the study area as control. Data collected was analyzed using SPSS version 20. The results
show that fields under intensified cultivation systems had significant reduction in soil available
water, soil nutrients and microorganism presence. Also, the results indicate that 95% of
respondents face the problem of high production cost (resulting from high cost of agricultural
inputs) and a decline in yields even with the use of agricultural intensification methods and
improved crop varieties. Thus, the premise of the study was valid. The results suggest a need for
the capacity of farmers to be built to implement sustainable forms of agricultural intensification
to be able to the reduce impact of current practices on fertility and by so doing increase their
agricultural productivity.
Key words: Degradation of agricultural lands, land use intensification, rice fields, soil nutrients
status.
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FOREWORD
Improving Ghana’s agriculture is pivotal in ensuring food sufficiency for the country as a whole.
Doing this would require the maximum use of arable lands with sufficient fertility levels. The
study is to clearly ascertain how using intensive practices of farming has affected the fertility of
soil and yields in the study area based on quantitative analysis and local farmers perceptions. The
study contributes to the data required by the Ministry of Food and Agriculture of Ghana to
understand and support local farmers in the implementation of sustainable forms of agriculture
and soil management.
I would like to thank Dr. Mark Appiah, who is the main supervisor of my thesis, for his guidance
throughout the study. I would also thank Dr. F.M. Tetteh for assisting me with the analysis of the
soil.
I thank my husband Mr. Roland Andy Adapaura for his moral and financial support throughout
the study.
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1. INTRODUCTION ..............................................................................................................................6
1.1 Background of the Study .........................................................................................................6
1.2 Problem Statement ..................................................................................................................7
1.3 Research Questions .................................................................................................................8
1.4 Research Objectives ................................................................................................................8
1.5 Significance of the Study..........................................................................................................8
1.6 Organization of the Study ........................................................................................................9
2 LITERATURE REVIEW .......................................................................................................................9
2.1 Agricultural Intensification (AI) ..............................................................................................9
2.2 Agricultural Intensification Measurements ........................................................................... 10
2.3 Economic Aspects of Agricultural Intensification .................................................................. 11
2.4 Soil Fertility and Agricultural Intensification ........................................................................ 12
2.5. Rice farming in Ghana ......................................................................................................... 13
2.5.1 Rainfed dryland ecology.................................................................................................. 14
2.5.3 Inland valleys .................................................................................................................. 15
2.5.4 Irrigated ecology ............................................................................................................. 15
2.6 Land preparation for rice production .................................................................................... 16
3 METHODOLOGY ............................................................................................................................ 18
3.1 Study Area............................................................................................................................. 18
Atwima Mponua...................................................................................................................... 20
Asante Akim Central Municipal and North............................................................................. 20
Ahafo Ano North ..................................................................................................................... 21
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3.2. Data collection ...................................................................................................................... 21
3.2.1. Soil Sample Collection .................................................................................................... 21
3.2.2. Interviews....................................................................................................................... 22
3.3. Analysis of the fertility levels in the laboratory ..................................................................... 23
3.4 Analysis of interview data ...................................................................................................... 29
3.4.1 Analytical Framework of Measured Study Variables ...................................................... 29
3.8 Ethics ................................................................................................................................. 31
4. RESULTS AND DISCUSSION ........................................................................................................... 31
4.1 Socioeconomic/demographic characteristics .......................................................................... 31
4.2 Mode of land acquisition by respondents (Land tenure) ........................................................ 34
4.3 Land use characteristics of farmers ....................................................................................... 35
4.4 Farmers Nutrient Sources ..................................................................................................... 37
4.5 Impact of intensification practices on Soil fertility Status ...................................................... 38
4.6 Challenges of Intensive Farming in study areas ..................................................................... 40
5. CONCLUSION AND RECOMMENDATION ........................................................................................ 42
REFERENCES .................................................................................................................................... 43
APPENDIX ........................................................................................................................................ 47
Appendix 1 Questionnaire ........................................................................................................... 47
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LIST OF TABLES
Table 1. The areas where soil samples were collected in Ghana .................................................. 22
Table 2. The number of individual rice farmers sampled from the respective districts Study ..... 23
Table 3. Titre value table used to calculate the percentage Carborn and Organic Matter ............ 27
Table 4. Variables used in interview data collection ................................................................... 30
Table 5. Bio characteristics of household respondents ................................................................ 33
Table 6. Characteristics of farmers’ land uses in the study area ................................................... 36
Table 7. Perception of farmers on their adopted agricultural practices ........................................ 36
Table 8. Farmers’ main sources of fertilizer used in rice production in the study area ................ 38
Table 9. Fertility Status of soils in the Ashanti region covering also the study ........................... 39
Table 10. Soil fertility status of Intensified (AI) and Non Intensified (NI) fields of the study area
....................................................................................................................................................... 40
LIST OF FIGURES
Figure 1. Location of study area in Ghana- Source: (Survey Department, 2009) ........................ 19
Figure 2. Texture Triangle ............................................................................................................ 25
Figure 3. Mode of Land Acquisition in the study area ................................................................. 34
Figure 4. Challenges of agricultural intensification practices in the study area ........................... 41
LIST OF ACRONYMS
AI
Agricultural intensification
FAO
Food and Agriculture Organization
FC
Forestry Commission
MoFA
Ministry of Food and Agriculture
GDP
Gross domestic Product
INGER
International Network for Genetic Evaluation in Rice
WARDA
West Africa Rice Development Association
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1. INTRODUCTION
1.1 Background of the Study
An average of 70% of Africa’s population live in rural areas and their livelihood is through
agriculture. About 40% gain foreign currency from trading internationally with agriculture and a
greater portion of their Gross Domestic Products (GDP) is from agriculture (Frederick, et al
2010). There is much evidence that agriculture contributes to both local and national economic
growth (Frederick, et al 2010). In an agriculture-based economy like Ghana, agriculture
contributes about 32 percent of GDP growth. But, agricultural activities in Ghana are still being
conducted with simple farm tools and equipment and limited fertilizer inputs consequently
productivity is low. In contrast, in transforming countries like China, India, Indonesia, and
Morocco, agriculture activities are heavily mechanized even though, the sector does not
contribute much to the growth of their economies. Agriculture contributes just about 7% of their
GDP.
In the case of some Latin American countries, agriculture provides below 5percent of GDP
growth (Gobind, 2009). In these two groups of countries agricultural mechanization has
contributed to increased agricultural output enabling them to achieve sufficiency in food
production. Thus, to achieve a higher level of agricultural productivity and agricultural
development, policy has to embrace agricultural intensification (AI) which has been defined By
Ruthenberg (1980) as designs of land-use that includes a higher usage of resources that are
fixed usually because of continual usage of the same area of land (Binswanger, et al. 1993).
AI increases the worth of its outcome (Tiffen, et al. (1994) and this happens because of a high
portions of materials that are added without a change in technologies (Frederick, et al 2010).
However, AI can also reduce the productive potential of agro-ecosystems if not properly
managed. As agriculture has become specialized and intensified, there have been landscape level
trends for a reduction in biodiversity and soil (FAO, 2011). Continues process of cultivation of
the land and low use of organic materials on fertilization significantly contributes to the
depletion of soil nutrients (e.g. Purvis & Bannon, 1992; Pedro, 2002). Also, land degradation,
deforestation and drying up of rivers are side effects of agricultural intensification (Vitousek et
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al. 1997; Tilman et al. (2001). Some effects which takes time to be evident include salinization,
loss of biodiversity, high carbon levels released into the atmosphere, loss of soil organic matter
which in the long run affect global climate.
Increased reliance on chemicals, which are often used under AI, also may have negative effect
on the environment and thus sustainable agriculture is very necessary (Pretty et al. 1996: 16).
This means that improved AI programmes including appropriate utilization of fertilizes are
needed (Tilman, 1999). The AI can be improved if ecological and soil conditions of farming
known and are assessed from time to time (MEA 2005). The aim of this study is to assessing the
interface between intensifying agriculture and its subsequent impact on soil fertility.
1.2 Problem Statement
Whilst population increase in Ghana demands greater amount of food to feed the populace
through mechanize agriculture and agricultural intensification, soil and its fertility is largely
affected. Yields are gradually dropping throughout Ghana including the study areas (Adansi
South, Atwima Mponua, Asante Akim Central, Asante Akim North and Ahafo Ano North)
according to MOFA SRID, (2010) due to continue cultivation without appropriate conservation
practices and soil improvement measures. An increased shortfall annually in the levels of N and
P in soils that have been continuously cultivated with crops that demand those nutrients. Most
frequently cultivated soils also become susceptible to erosion. Furthermore, biodiversity within
agro ecosystem are also affected as a consequence of declined soil fertility.
Different studies have results showing impacts of agriculture on biodiversity and soil fertility.
This include how agricultural intensification practices influence species abundance and richness
(Vickery et al. 2001, Fuller et al. 2005 (Krebs et al. 1999; Tilman et al. 2001), The fertility of
the soils changes in reaction to the type of agricultural intensification practice (Chamberlain et
al. 2000). The effects that results from agricultural intensification practices within agro
ecosystems are poorly documented, particularly for Africa. This study was designed to fill in the
gap in knowledge by assessing the soil conditions and examining farmers’ perception of the
effect of intensification on the soil fertility using less intensively managed systems as control.
The study attempts to answer the following research questions:
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1.3 Research Questions
1. What are socioeconomic background of rice producers in the study area and impacts on
cultivation practices?
2. What are the impacts of intensive practices of rice farming on soil fertility
3. What are the farmers’ perception of the problems facing the intensification of the
agricultural practices, in this case being rice farming?
1.4 Research Objectives
General Objective
1. The general objective of the study is to generation information on the impact of
agricultural intensification on soil fertility. This information could be useful for
developing appropriate strategies for conserving soils within landscapes used for rice
farming.
Specific Objectives

Determine farmers’ socioeconomic conditions affecting the choice of land use practices
in the study area and the challenges facing agricultural intensification.

Assess the soil fertility status of rice farms under intensive management systems through
laboratory soil analysis.
1.5 Significance of the Study
Our understanding of soil fertility changes in small-scale agricultural system in Ghana and
Africa as whole remains poor. In fact Soil fertility are highlighted as major issues for agricultural
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development in Ghana and Africa as whole. This study offers information that could be useful in
soil management decisions. Expected outcomes of the study include the following:

The characteristic of farming systems and their association with soil fertility determined

The extent of soil fertility status and loss determined for selected fields

Recommendations for management and policy decisions proposed.
1.6 Organization of the Study
Chapter one covered the introduction of the study, followed by chapter two which reviewed
relevant literature on agricultural intensification agricultural practices, and soil fertility. Chapter
three also focused on the methodology of the study. The chapter looked at the research design
and sampling framework. This is followed by chapter four where the results are analyzed and
discussed. Lastly chapter five presents the study conclusion and management recommendation.
2 LITERATURE REVIEW
2.1 Agricultural Intensification (AI)
Increasing population growth in Ghana has led to continual usage of farm land so as to cater for
the high food and other agricultural products demands (Benites &Vaneph, 2001). The use of
intensified farming requires mechanized farming with effective and efficient machinery. As a
result, land area under cultivation has increased with a gradual shift to the cultivation on one
crop continuously. Also crop rotation is least practiced reducing fallow periods on lands that are
cultivated. .
Tillage associated with intensive farming impacts on the structure of the soil which does not
encourage favourable crop development because of degradation of the structure of the soil
(Huwe, 2002). The level of modification of the soil and the extent of negative damage depends
on the type of soil, organic matter contend, soil moisture and the time of ploughing. Generally,
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soils with high levels of silt and low clay and organic matter content mostly sandy and sandy
loam soils are at a greater risk of damage mechanically.
Most AI practices specilises in crops and livestock species with high management involvement.
Different forms of Agricultural intensification at varying levels. These include shifting
cultivation where land is utilized in less than a year out of a total of ten years. For fallow systems
land is utilized between one and two-thirds at a time and this can be viewed as systems of
varying intensity Ruthenberg, 1980. With this increasing level of land use, intensification
replaces manual labour with mechanized machinery also organic manure with agrochemical
usage. . Levels of agricultural input utilized can change significantly at different levels between
internally regulated systems to externally regulated systems. Also can vary from sustainable
methods to unsustainable systems within a short time duration. Another factor used to identify
the level of intensification is the season within the year thus dry or wet season’s management is
required through irrigation or wiers (Flohre, 2011).
2.2 Agricultural Intensification Measurements
Grace Carswell, (1997) explained that agicultural intensification processes involved an increase
in the number of times of cultivation for the same piece of land, a higher labour cost as well as
technological changes.
There should also be prove of the usage of chemical fertilizer, animal
traction, machinery, improved seed and soil conservation methods. This would imply
intensification is evident. Therefore for Agricultural intensification to occur, there should be a
higher inputs on a fixed area of land, the number of times the soil is cultivated and total
productivity.
Cropping times can be determined by the period of time that a piece of land is used for farming
activities viewing an increased number of cropping to be immediately after intensification. But a
move from crops that have higher yield that mature within 100 days within a year to crops with
low yield that mature in about 250 days a year would not be described as intensification even
though the move may result in increased labour. Also an area could be intensified but would be
without fallows like in Kabele, Uganda (Lindblade et al. 1996).
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When there is an increase in the output per hectare of an intensified area is a possible increase in
the quantity and quality of the livelihood as well as livelihood sustainability. Opposite of TFP as
a measure tool by Binswanger, et al. (1993), Ruthhenberg, (1980) gave a different measurement
perspective to agricultural intensification. Another criteria that is used to identify the extent of
intensification in areas that are arid by seasons, wet climates and in production systems is how
water is managed through drainage or irrigations systems. Thus intensification is associated not
only with land use intensity, labour inputs and nutrient usage with internal recycling, but also
with pest management and water management (Ruthenberg, 1980). For intensification practices
to impact soil biodiversity positively, these factors must be available in sustainable levels and
appropriate management options developed for the management of these factors.
2.3 Economic Aspects of Agricultural Intensification
Agricultural Intensification can be considered as justifiable economically and also sustainable if
the perceived economic cost can be lower than economic benefits in its long term. The cost of
Intensification can include using improved varieties of seed or plants, farm consumables like
fertilizer and fuel, investments made in mechanization, cost of labour in maintainace, operational
and other repairs (Dbowen, 2012). The advantages can be an improvement in yield, pest resistant
plants, drought resistant plant which means there would be crop reliability. Therefore if the
benefits obtained in the long term does not satisfactorily outweigh the cost involved,
intensification would be considered unsustainable and not a venture that should be promoted,
This if the benefits supersede the input cost, then farmers should bear the cost of intensification
and achieve a very significant output (Dbowen, 2012).
Farming has a very high level of uncertainty and as such the risk is very high and affects the
profits involved. Some of the risks include drought, insect infestation, diseases, political and
unstable markets. Under traditional farming methods, seed are saved form seasonal harvest and
family labour is utilized. On the other hand, intensification requires investments directly in
fertilizers, herbicide, mechanized techniques, improved seeds etc. Benefits would only be
obtained after these investments are made even though similar farming risk such as drought,
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disease infestation presents itself. Notwithstanding, intensification has potential loss of
indebtedness or increased production cost (Dbowen, 2012). Therefore, if there is a move from
traditional farming to intensification, farmers will have the extra risk of intensifying farming risk
to the extent that a trade-off cost upfront and future perceived benefit in yield may not be
attractive. For farmers to be convinced of intensification practiced, donor organizations usually
supply inputs like seed, improved technologies of farming, chemical fertilizers at a reduced cost
or in some cased at no cost. Although this approach could also lead to continual dependency on
donors (Dbowen, 2012).
2.4 Soil Fertility and Agricultural Intensification
The maintenance of soil fertility and access to water are essential to food production according to
Westarp, (2002). This is of particular relevance to the subsistence-based farming systems of the
Sub Saharan Africa especially in Ghana, which face tremendous pressure to feed a rapidly
growing population and the need agricultural intensification to increase food production.
Agriculural intensification will require that soil fertility level are good. However, soil fertility is
declining in most of the agricultural landscapes in Ghana.
Westarp, (2002) study investigated if soil fertility has been compromised through agricultural
intensification by comparing the soil status and inputs in intensively managed sites (sampled in
2000) to those of less-intensively managed sites (sampled in 1994). Nutrient budgets for nitrogen
(N), phosphorus (P), and potassium (K) were developed to examine if inputs of these nutrients
are sufficient to meet crop uptake. It was found that intensive farms utilize significantly more
fertilizer and compost than less-intensive sites (Westarp, 2002). He concluded that cropping
rotation under intensive agriculture have higher nutrient uptake than rotations under less
intensification. He added that the intensification of agriculture in the area altered the soil fertility
dynamics of phosphorous and potassium.
A great number of living organisms of diverse origin are contained in the soil and they are
classified into complex and varying communities in which they live. The FAO (2002) underlines
that biodiversity found in the soil indicates the varying living organisms in the soil and they
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could range from those microorganisms that cannot be seen including bacteria and fungi to those
macro fauna that can be seen like earthworms and termites. The roots of plant could be said as
part of soil organisms because of their symbiotic relationships and the way they interact with the
various components of the soil (Anderson & Domsch, 1989; Oades, 1993; Smith et al., 1994;
Kennedy & Papendick, 1995). The varying organisms interact in different ways with the plants
and animals found in the ecosystem which forms a complex form of biological activity (FAO,
2002). Those factors that affect the environment like temperature, moisture, acidity and other
anthropogenic factors like agricultural and forest management activities tend to affect the various
soil biological communities as well as the way they function. Thus affecting the health and
quality of the soil. But soil quality are needed in either within the natural or ecosystems that are
managed with boundaries in order to hold on to plant and animal production, and thus enhance
the quality of water and air as well as support the health of humans. Soil health includes
ecological contribution of the soil, which include beyond the quality and capacity to produce a
particular king of crop (FAO, 2002).
2.5. Rice farming in Ghana
There has been a fast change in the diet of Ghanaians especially within the urban communities
after the country’s independence in 1957. This change has largely been attributed to rising
income levels, favourable government policies, better storability of rice and its ease of cooking
(Nyanteng, 1987). The per capita per annum rice consumption in Ghana increased form 7.4kg to
13.3kg between 1982 and 1985. This resulted in the total annual consumption of 23900 tonnes of
milled rice at and estimated population of 18 million. Between 1991 and 1996, consumption
increased to 119000 tonnes over the previous figure. The core of the motivating factor which is
governmental policy was attributed to the Medium Term Agricultural Development Policy which
involved exploring the vast inland valleys and swamp areas in the country, reducing emphasis on
conventional irrigation schemes, and at the same time researching into rice production as well as
increasing the engagement in technological transfer to make production efficient (Nyanteng,
1987).
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In Ghana, rice is cultivated in all ten administrative regions of the country which covers all the
major ecological zones including the savannah zone, high rain forest zone, semi deciduous forest
and coastal savannah. Each ecological zone has a distinct rice ecosystem which could be
Rainfed, dryland, Rainfed lowland, inland and valley bottom and irrigated paddy fields
(Nyanteng, 1987). Rainfed ecology accounts for about 75percent of production area whilst
irrigated fields contribute about 10 percent with inland valleys adding about 15 percent.
2.5.1 Rainfed dryland ecology
According to (Nyanteng, 1987), this ecology is characterized by higher slopes within the
toposequence where crops cultivated obtain their water requirement mainly from rainfall and not
from high underground water table. Weed competition is very high in this ecology making it
favourable for upland weeds like Rottboelia exaltata, Tridax procumbens, Cleome viscose,
Commelia spp etc to grow. When rainfall levels are low and inconsistent, weed growth are
enhanced and making weed control the major issue within this ecology. As such controlling
weeds in this ecology is a basic requirement if rice cultivation is to be successful. Cultivation of
low yielding variety such as Oryza glaberrima is very common in this ecology.
Some of the traits that have favoured the continuous cultivation of these local varieties include
their tall nature of growth making it a good competitor with weeds, its tolerance of some adverse
soil conditions such as drought, low fertility and high acidity. Also they better withstand diseases
and insect pest as well as having a good aroma when cooked.
Much emphasis should be placed on cultivating improved varieties such as Basologo (GR 19)
and Faro 15 Gr 21. Some of the above mentioned varieties are being tested for release to farmers
by the crop research institute and savannah agricultural research institute. Common pest found
here are rodents and bird. Thus it becomes necessary to fence the fields in order to protect them
from large rodents, grass cutter so that the crops are not destroyed. Low inherent soil fertility and
erratic rainfall as well as the low technological know - how are some of the other challenges in
this ecology (NARP 1994).
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2.5.2 Rainfed lowland ecology
The flood plains of rivers dominate this ecology and are located interior of the savannah where
the topography is gently undulating. Water availability is higher than the rainfed dryland. Water
levels differ with the height of flood and as floods decrease, the crop obtains its required water
from the high water table. Sixty percent of rice area in Ghana is covered by the rainfed lowland
ecology and more than 80% of rice area in the interior savannah are also rainfed lowland where
rainfall season is once a year.
The rainfall patter is between May and November which leaves most rice field under water for
extended periods. The flash floods usually affect field activities such as application of fertilizer,
weed control, bird scaring and harvesting which tend to reduce yields. Weed and water
management, use of low yielding varieties as well as poor soil conditions is the major defect of
this ecology (Nyanteng, 1987).
2.5.3 Inland valleys
A wide area of land is represented by inland valleys and they remain unexploited for rice
cultivation. About 30% of cultivable inland valleys are yet to be effectively cultivated.
2.5.4 Irrigated ecology
The irrigated area under cultivation is lower than that of rainfed lowland and inland valleys. But
the reliability and sustainability of production is much higher than that of rainfed ecology
because production is under control and the output per unit area is around 3.5- 7 ton/ha. Irrigated
area can be said to be of superior importance than the remaining ecologies which have an
average of 2tons/ha or even less.
Extensive education and research has gone into irrigated ecology development by the University
of Ghana Agricultural Research Station in collaboration with West Africa Rice Development
Association (WARDA). This has resulted in the development of several improved varieties for
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farmers’ trial. This ecology is also associated with a high level of improved technologies
application (WARDA 1986).
The main constraint within this ecology is the high bird and rodent population which reduces
yield resulting to the poor participation of farmers in rice production in this ecology. Continuous
mono-cropping of rice is a common feature in this ecology because of a lack of sustainable
option within the rice basins. Unfortunately, this results in depriving the soil of the needed
nutrients and increasing diseases and consequently adding up to the challenges of this ecology.
Weed control is also said to be a problem within this ecology. Some of the common weed found
under
irrigated
fields
are
Ischaemum
rugosum,Echinochloa
colonum, Cyperus
rotundus and Phyllanthus spp. The withdrawal of subsidies on inputs has increased the challenge
of weed control especially farmers resorting to hand weeding which causes reduced farm sizes.
Low infrastructure of agricultural inputs like reapers, threshers, transplanters, combine
harvesters, power tillers also affect the output within this ecology (Nyanteng, 1987).
2.6 Land preparation for rice production
Land preparation is a very vital activity in rice cultivation. The land is prepared adequately in a
way that reduces weeds, nutrients can be reused, a good surface which can be used for direct
sowing etc. Preparing the land could involve farming practices such as zero tillage or minimal
tillage which reduces the disturbance of the soil to a well puddle field which could destroy the
structure of the soil. The process of land preparation could include tilting, harrowing and land
leveling. Harrowing the field helps break down the lumps of the soul formed after ploughing as
well as return the plant residue into the soil which helps improve upon the structure of the soil.
Leveling the land also help in equal distribution of water and nutrients on the paddy field. Land
preparation could take about 3weeks before planting is done (Oteng 1994).
Land Till/Tillage:
According to (Oteng 1994), the method of conservation tillage involves crop residue from
previous planting season that is left on the fields before the next cropping. The method helps to
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reduce soil erosion by conserving the top soil. For this benefit to be achieved, about 30% of the
field should be covered with plant residue. This method is appropriate for areas where the soil is
prone to erosion.
The following are different types of conservational tillage that are practiced.
1. Strip till
2. No til
3. Ridge till
4. Mulch till.
Strip till and No Till:
This include the cultivation of crops into the residue left on the field without any
tilling or only tilled narrowly at the edges and the rest of the field left.
Ridge till:
Planting on permanently mounted a ridge which is about 4-6 inches horizontally
in height. The residue from the previous season is usually cleared from the top to
the ridge in order to make way for the new plants.
Mulch Till.
About a third of the field is covered with the crop residue or mulch.
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3 METHODOLOGY
3.1 Study Area
The study was carried out in Ashanti Region involving five (5) selected farming districts namely;
Adansi South, Atwima Mponua, Asante Akim Central, Asante Akim North and Ahafo Ano
North (Figure 1). The region and selected districts falls within the semi-deciduous agroecological zone of Ghana. The region can be found of the latitude of 6°52’N and longitudinally
at 1°51'W. Also the altitude of the region is about 280m above sea level.
The region has two rainy seasons within a year with the first starting from May – June. The
Second season is around October every year. The rainfall averages within the region are between
1100mm and 1800mm. The average temperature daily is about 27oC. The region is densely
populated with the average density being 148.1 per square kilometer and which is after the
Greater Accra Region. A greater part of the region lies within the wet forest zone. As a result of
anthropogenic factors, the northern part of the region has been changed into savanna.
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Ashanti Region
Figure 1. Location of study area in Ghana- Source: (Survey Department, 2009)
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Adansi South District
The population of the district as per 2006 information gives a density of 110.4 person to
59kilometers. This means a greater population pressure on resources especially land. The number
of communities’ totals 1767 and households totaling 17032. The population practices mainly
monocropping, plantation cropping and mixed farming. Traditional farming tools are mainly
used with slash and burn being the main land preparation method. Also shifting cultivation is the
most common farming method used within the district.
Atwima Mponua
The most common farming system in practice here is the Monocoropping. Other form also
practiced is the mixed farming. The use of the hoe and cutlass are dominate as the farming tools
used for cultivation. A period of between 1 and five years are usually left between cultivation in
which the land is allowed to fallow. The main vegetation here is the Semi-deciduous. There is
diversity in the soil fauna and flora. Some of the economic trees present within this district
include Wawa, Sapele, Esa and Asafena. The vegetation of the District has been extensively
disturbed by human activities depriving the District of valuable tree species and other forest
products. Soils are generally very suitable for cultivation and can be categorized into two.The
moderately suitable soil and marginally suitable soils.
Asante Akim Central Municipal and North
The district was divided from the Asante Akim North Municipal Assembly.The capital of the
district is Konongo Odumase. The location of the district is between Latitued 60 30’ North and
00 15’ longitude. It shares boundries with Sekyere East, Kwahu South, Asante Akim and Ejisu
Juaben Municipal on the West. Some of the common forest trees are Wawa, Ofram, Sapele,
Sanfina, Okyere, Onyina etc. There has been forest degradation in the district and as such
primary forest has been lost.
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Ahafo Ano North
The geographical location of the district is at latitude 6˚ 47’N and 7 02’N and longitude 2˚ 26’W
and 2˚ 04’W. It lies in the north western part of the region. The surrounding districts include
Ahafo Ano South, Atwima, Asutifi and Tano South districts. Farmers in the district are
predominately cash crop farmers due to the high fertility of soils in the district (DDP, 2006).
3.2. Data collection
The study used different methods to address the different research questions including laboratory
tests and qualitative methods (direct observation, and interviews). Field data were collected in
2013. Desktop study was also done to review relevant literature from current articles, journals
and other published and non-published data related to agricultural intensification, soil fertility
losses, rice farming, and general information on districts. The main sources of secondary data
were technical reports obtained from the Ministry of Food and Agriculture (MOFA), Forestry
Research Institute of Ghana (FORIG), Forestry Commission, District Assemblies and from the
Environmental Protection Agency (EPA) of Ghana.
3.2.1. Soil Sample Collection
In order that fertility could be measured,
soil samples were collected in at least two types of
fields (i.e. intensified fields and non-intensified fields) from each study area. To avoid sampling
error and ensure uniform sampling areas, the soil samples were collected from fields with similar
slopes, slope length and farming. Other criteria used for selection was land-use intensity and the
type of crop grown. During the soil sample collection process, the owners of the plots were
interviewed for specific information such as agricultural practices and past land-use.
22
A soil auger and a soil probe was used as sampling tools to take soil samples at a depth of 30cm
of top soil and sub soil. Plastic bucket and rubber was also used for the collection of the samples.
Twenty samples of top and sub soils were collected to assess physical and chemical properties.
The co-ordinates of the soil sample locations were also recorded by a GPS (Table 1).
Table 1. The areas where soil samples were collected in Ghana
District
Community
Coordinates
Adansi South
New Edubiase
N 06 39 16.4, W 001 1243.7
Atwima Mponua
Kensah Krom
N 06 06 58.0, W001 28 76.3
Asante Akim
Atonsu
N 06 39 14.4, W001 12 38.8
Ahafo Ano North
Tepa
N 06 04 48.0, W001 24 56.3
3.2.2. Interviews
Data on tree resources and perception on soil fertility was obtained by asking farmers questions
using both closed and open ended questions. The questionnaires were administered to 200
farmers (out of a total population of 3350 rice farmers) selected from the 5 selected districts of
the region. Purposive sampling was used to select the rice farmers based on the intensification
practices. After which a random and proportional sampling was done to ensure that every
respondent have the equal chance of being interviewed within the study. Using ratios and
proportions, the sample size was derived as follows in (Table 2).
23
Table 2. The number of individual rice farmers sampled from the respective districts Study
Districts
Farmer
Sample Size (n)
Population
Ahafo Ano North
687
41
Adansi South
1500
90
Atwima Mponua
594
35
Asante Akim North and Central
569
34
3,350
200
Total
3.3. Analysis of the fertility levels in the laboratory
3.3.1 Sample Preparation
Prior to the soil physical and chemical characterization, sampled soil were air-dried, later
crushed and sieved through a 2 mm sieve.
3.3.1.1 Characterization of soil (Physical properties)
Particle size analysis
In measuring the percentages of primary soil separates, Bouyoucous hydrometer method was
adopted (Day 1965). Each sampled horizon was analyzed for its particle size distributions (i.e.
clay, sand and silt content).
The weight of a beaker was taken using a weighing balance and fifty grams (50 g) of the 2 mm
sieved soil was weighed and 20 ml of H2O2 was added to oxidize the organic matter. 100 ml of
Calgon solution (Sodium hexametaphosphate and sodium hydrogen carbonate) was added to the
24
mixture in the beaker and stirred. The mixture was then heated for the first sigh of boiling while
stirring and thereafter poured through the 53 µm sieve into a settling cylinder and topped to the
1000 ml mark with distilled water. The retained material on the sieve was then washed off into a
beaker and allowed to settle for 24 hours. Water on top of the settled mixture was then poured
off and heated to evaporate all moisture to obtain the dried sand fractions. After agitating the soil
suspension with a plunger, the time was noted immediately. A hydrometer (ASTM 15 2H) was
then placed into the soil suspension and the first and second readings recoded after 5 minutes and
5 hours respectively. Thereafter, the soil suspension in the cylinders was poured onto a 53 µm
sieve. Retained soil particles on the sieve was thoroughly washed with water into a beaker of
known weight and dried in an oven at 105 °C for 24 hours.
The oven dried samples were then placed in desiccators and weighted to represent the sand
fraction. Equation (Eq) 1 – 4, represents the formulae used in determining the particle size
distribution of each soil horizon sample.
The texture triangle as indicated in Figure 2 was further used to determine the textural classes
(primary soil separates sand, silt and clay) of each soil sample.
25
Figure 2. Texture Triangle
Determination of Gravimetric Soil Water Content
Samples collected with the cylindrical core sampler was weighed and transferred into a moisture
can of known weight. The samples were then oven dried for 24 hours at 105 degrees and later
weighed after cooling it in a desiccator. Eq. 5 represents the formula used to estimate the
gravimetric soil water content of each sample.
Where A is the mass of empty container in grams, B is the mass of empty container and moist
soil sample in grams and C is the mass of empty container and dry soil sample in grams.
26
3.3.1.2 Characterization of soil (Chemical properties)
Determination of Soil pH (1:1)
Twenty five grams of the soil sample was weighed into a 50 ml beaker. In a ratio of 1:1, 25 mls
of distilled water was then added. The soil suspension was then stirred for 30 minutes at 5
minutes interval. The suspension was then allowed to stand for an hour to allow the entire
suspended particles to settle. A glass electrode pH meter was standardized with two aqueous
solutions of pH 4 and 7. The pH of the prepared suspension was then measured and recorded by
dipping the glass electrode into the soil suspension.
Determination of Total Nitrogen
Determining soil percentage total nitrogen involved three (3) stages; (1) digestion, (2) distillation
and (3) titration. 0.2 g of air-dried soil sample was weighed into a 250 ml Kjeldahl flask
followed by addition of digestion accelerator, selenium catalyst and 5 ml of concentrated
sulphuric acid (H2SO4). The mixture was allowed to digest until the digest was clear. It was then
allowed to cool and then transferred with distilled water into a 50 ml volumetric flask and made
up to the volume. A 5 ml aliquot was pipetted from the digest into a distillation flask and 20 ml
of 10N sodium hydroxide (NaOH) was added with 150 ml distilled water. The sample was then
distilled and collected in 25 ml of boric acid. The distillate was then titrated against 0.02 N HCl
(Bremner, 1965) to attain the end point. The amount of N (%) was then calculated.
Determination of Organic Carbon and Organic Matter
Wet combustion method of Walkley and Black (1934), was used to determine organic carbon. In
this method, One (1) gram of soil sample was weighed and 10 mls of 1N potassium dichromate
(K2Cr2O7) solution added. Twenty (20) ml of 98% concentrated sulphuric acid (H2SO4) were
added to the prepared mixture and allowed to stand for 2 hours to ensure complete digestion. A
27
30 mls blank solution was then prepared at a ratio of 1:2 (i.e.1 ml K2Cr2O7solution is to 2 mls of
H2SO4) and the blank factor determined by Eq. 8.
Further on, the remaining unreacted K2Cr2O7 in the solution after the digestion was titrated
against 0.2 M ferrous ammonium sulphate using barium diphenylamine sulphonate as the
indicator to give the end point. The titre value was used to calculate the % C and Organic Matter
(Table 3)
Table 3. Titre value table used to calculate the percentage Carborn and Organic Matter
A
Titre value
B
A x bf
C
D (Amount of
(amount of K2Cr2O7 used)
CO2 evolved)
10
C-B
O.C.
O.M
DxK
O.C. x T
Where K is a constant (0.39), T is 1.724 (i.e. there is about 58% of O.C. in O.M.)
Determination of Available Phosphorus
Available P of the soil was determined using Bray-1 solution. Five (5) grams of soil sample was
weighed into the extraction bottle and 35 mls of Bray I solution added. It was then capped and
shaken for 30 min on a mechanical shaker. The extracts were filtered using Whatman’s No. 125
filter paper to obtain clear filtrate. Five (5) mls aliquot was taken into a test tube and then ten
(10) mls of colour reagent (colour reagent was prepared from 40 grams of ammonium
molybdate, 4 grams of bismuth sub carbonate, 300 mls of sulpharic acid and distilled water)
added. A pinch of ascorbic acid was then added to reduce the P to form the blue colour. The
mixture in the test tubes was swirled for colour development and phosphorus analysis.
Concentrations of P in the mixture was then determined using the spectrophotometer. Available
phosphorus content of the soil was calculated by Eq. 9.
Where X is the absorbance and 7 is the extraction ratio (i.e. 1:7, 5 g soil: 35 mls of Bray I
solution).
28
Determination of Effective Cation Exchange Capacity
Ammonium acetate (NH4OAc) pH 7.0 method was adopted to determine the CEC of the soil. To
mimic field conditions, leaching tubes were used. Leaching tubes were filed with cotton and 2.5
grams of soil sample weighed into them. Fifty (50) mls of NH4OAc at pH 7 was measured and
poured into the cotton filed leaching tube with soil sample. The setup was allowed to stand for 2
hours to ensure maximum leaching of exchangeable bases. The leachate was then taken for
elemental analysis. Here, atomic absorption spectrophotometer (AAS) was used to determine the
concentrations of Magnesium (Mg) and Calcium (Ca) and further used the flame photometer to
analyze the leachate for the concentrations of Sodium (Na) and Potassium (K).
Determination of Exchangeable Acidity and Hydrogen
In determining Exchangeable Acidity, as indicated by Mclean, E. O. (1965), three (3) grams of
soil sample was weighed unto a folded filter paper placed on an extraction cup. 50 mls of 1.0 N
KCl solution was measured and gently poured into the soil on the filter paper for filtrate to be
collected. Five (5) drops of phenolphthalein indicator was then added to the filtrate and titrated
with 0.05N NaOH to obtain a pink end point. The titre volume (in mls) of NaOH used was then
recorded. Eq. 10 below was used to calculate the exchangeable acidity of the soil sample.
Where V is the titre volume of NaOH used (ml), 0.05 is the normality of NaOH, W is the weight
of soil sample in grams.
In addition, exchangeable aluminium was later determined by the addition of four (4) mls of
3NNaF to the titrated extract and the mixture titrated again with 0.05NHCl to obtain a pink end
point. The titre value of HCl used was the recorded and exchangeable aluminium in soil
calculated from Eq. 11.
29
Where V is the titre volume of HClused (ml), 0.05 is the normality of HCl, W is the weight of
soil sample in grams.
3.4 Analysis of interview data
The data collected were subjected to descriptive and quantitative analysis with the use of bar
charts, percentages and frequency distribution tables. SPSS and Microsoft excel sheets were used
for the analysis. Pre coding of data was also done to assist in the analysis. Chi square test was
used to measure differences of the variables for observed and expected intensification impacts on
the ecosystems, biodiversity and soil fertility levels in the study areas. Qualitative and
quantitative methods such that respondent answered in a nondirective manner (McCracken 1988,
in Hoggart, Lees and Davies, 2002). Thus the benefit of using the quantitative approach is to
make research easier and fast so as to cover a large area within where the situation pertains.
(Amaratunga et al 2002).
3.4.1 Analytical Framework of Measured Study Variables
Several measurable variables were used in the analysis of the primary data linking farmers
experience as bio-data to environmental and biophysical factors. The Table 4 below indicates the
category and types of variables used in the analysis for this study.
30
Table 4. Variables used in interview data collection
Variables
Levels of
Method of Analysis
Measurements
Age
Interval
Frequency, percentages, tables and graphs
Gender
Nominal
Frequency, percentages, tables and graphs
Education
Ordinal
Frequency, percentages, tables and graphs
Farm size/Acreage size
Interval
Frequency, percentages, tables and graphs
Household size
Interval
Frequency, percentages, tables and graphs
Household head
Ordinal
Frequency, percentages, tables and graphs
Number of dependants
Ordinal
Frequency, percentages, tables and graphs
Farming experience
Nominal
Frequency, percentages, tables and graphs
Household expenditure
Nominal
Frequency, percentages, tables and graphs
Source of agricultural water
Nominal
Frequency, percentages, tables and graphs
Agricultural inputs
Interval
Frequency, percentages, tables and graphs
Technologies used
Ordinal
Frequency, percentages, tables and graphs
Forest cover availability
Nominal
Frequency, percentages, tables and graphs
Number of years cultivated
Nominal
Frequency, percentages, tables and graphs
Soil compaction and fertility
Nominal
Frequency, percentages, tables and graphs
Methods of cultivation
Nominal
Frequency, percentages, tables and graphs
Types of crops cultivated
Nominal
Frequency, percentages, tables and graphs
Rainfall pattern
Nominal
Frequency, percentages, tables and graphs
Agricultural practices
Nominal
Frequency, percentages, tables and graphs
Biodiversity loss
Nominal
Frequency, percentages, tables and graphs
Conservation practices
Nominal
Frequency, percentages, tables and graphs
31
3.8 Ethics
Ethical issues were addressed by explaining to participants about the nature of the study and their
expected roles in answering the researchers’ questions. They were, needless to say, not under any
obligations to answer questions they did not like or wish. Participants consent forms were given
to them to sign and they were assured of confidentiality and protection of their identity in
accordance with the University ethical standards.
4. RESULTS AND DISCUSSION
4.1 Socioeconomic/demographic characteristics
The majority (164) of the respondents were male farmers representing 82% of total respondents.
The rest were (28 representing 14% of total respondents) were female respondents (Table 5).
This shows that the rice farming sector in the study areas is largely dominated by men and
confirm the statistics reported by Danso et al. (2002). This could be attributed to the culture in
the areas, economic situation and the drudgery nature of the agricultural activities. Again, it
could also be linked to the intensification practice as more of the women cannot be fully engaged
to practicing all year farming to the detriment of household marketing activities.
Farmer’s monthly income from their rice farming activities and other earnings in a month varied
among respondents. The majority (66%) earns not less than GHC 500.00($136.46 as at
26/11/15.) a month. 19% of the respondents earn between GHC 1000-1500 ($261-$391as at
26/11/15). Only few (1%) of the respondents earned GHC 2000 ($522 as at 25/11/15.) But the
general outcomes from all respondents are that all farmers interviewed are earning more than $60
a month, which is equivalent to the classification of rural income in certain areas in Africa by the
World Bank report on average daily and monthly wages. This is reflected in the spending pattern
32
of farmers as more of the farmers spent less than GHC 500 a month (82%) with 18% spending in
a range of GHcC500-1000 (Table 5).
The intensive farming activities in the study areas have resulted in their increased income and
expenditures. This agrees with the findings of Dbowen (2012) that intensive farming could lead
to an increased benefit in terms of income. The challenge, however, was the dwindling fertility
levels of the soils and the higher corresponding cost of inputs and labor for their farming
activities. Many of the farmers never added their family labor cost which helps them in the
intensification drive seasonally. Often such cost are excluded from the local people’s expenditure
and income calculations. However, the cost for labor per day in all the 4 study districts was GH¢
10 which is expensive based on their intensification levels and the frequency of agronomic
activities per crop cycle. This notwithstanding suggests that their intensification farming
practices appear profitable to the local people as they could be able to meet their household
needs.
One other characteristic of the respondents was that of their educational level. Senior High
School (SHS) and Junior High School (JHS) had the highest responses from the farmers with a
percentage score of 29% and 26% respectively. Only 1 person had tertiary education and 22% of
them had no formal education. With this, it indicates that a large number of the farmers are
educated, thus, can read and write.
33
Table 5. Bio characteristics of household respondents
Level
No formal education
Primary
Junior High
Senior High
Tertiary
Total
Sex
Male
Female
Age
18 to 25
26 to 35
36 to 45
46 to 55
Total
Amount (GHC)
<500
500-1000
1000-1500
1500-2000
>2000
Total
Educational levels of Respondents
Frequency
Percentage %
44
22
34
17
52
26
58
29
1
0.5
200
100
Sex of Respondents
164
28
Age of Respondents
82
14
2
54
68
60
200
Household Monthly Income
1
27
34
30
100
131
38
17
10
2
200
Average Monthly Expenditure
66
19
9
5
1
100
164
36
0
0
0
200
82
18
0
0
0
100
Amount (GHC)
<500
500-1000
1000-1500
1500-2000
>2000
Total
34
4.2 Mode of land acquisition by respondents (Land tenure)
Cultivation of rice has been done for a long time according to Mobil and Okran (1985). Land for
rice farming was mostly acquired through hiring (36%), and from family member through
inheritance (30%). Others obtained land through direct purchase and lease system. The other
forms of land acquisition included annual payments either through cash or in kind. This are
common ways of land acquisition in Ghana (Appiah 2001) and this process contributes more to
the overall farmers increased cost of production per season thus reducing the income levels of
the farmers. It also facilitates intensification as farmers are constrained to the same piece of land
without much fallowing of the lands. Migrant farmers usually do not own lands in Ghana. Thus
according to Jordan (1995), farmers who practice share cropping are mostly poor and landless
and they are allowed to farm for a season where they return part of their harvest to the land
owners. Most of the farmers interviewed too were migrant farmers which meant that they were
not the custodians of their farm lands leading to the leased, hired and purchase of the lands for
production (Figure 3). Majority of the farmers as well earns less than GHc 500 and the cost of
land only makes production worse for them.
Figure 3. Mode of Land acquisition in the study area
35
4.3 Land use characteristics of farmers
The results show that farmers use good agricultural practices to try to increase their yields:
practices such as conservative use of organic manure, land fallowing, crop rotation and
management of use of water resources (Table 6).
This is reflected in the soils showing good
signs of soil organic matter contents and activities including soil burrowing that helps in
aeration, loosening up soils for easy plant utilization and the decomposition of soil organic
matter. When soil microbial organisms are absent in the soil, fertility would be greatly affected
and this would in turn affect the healthy growth of crops (FAO 2002). Due to the activities of
bacteria, algae, fungus, millipedes etc, organic matter are broken down resulting in its
availability to plants for normal development.
The cycling of elements as nitrogen, carbon and phosphorus is crucial for rice growth as they are
essential for the growth and development of all crops (Westarp, 2002). When farmers engage in
practices such as fallowing, application of organic manure or composting, these elements are
able to be retained in the fertile layer of the soil for crop use. As a result, farmers are encouraged
to use these conservation techniques for more soil living organism like the earthworms, ants,
millipedes to work and burrow the soil for aeration, breakdown of organic matter and enhance
soil percolation; this are vital process for developing a healthy soil (FAO 2002). Unfortunately,
several years can pass before these elements can be form that are very vital for the growth of
plants. For a crop as rice in particular and like other cash crops like cocoa advance land
preparations are needed to be able to achieve a good fertility status with such elements present in
adequate amount.
As the results show, it is improving the humus and subsequently soil fertility status of the soils
that has made these local practices attractive ways of maintaining the soil for higher yields and
sustainable production (Table 7).
36
Table 6. Characteristics of farmers’ land uses in the study area
Land use features
Crop rotation
Fallowing
Use of organic manures/compost
Yes
(%)
60
80
40
responses No responses
(%)
40
20
60
Total
(%)
100
100
100
Tillage
Use of chemicals
95
60
5
40
100
100
Slash and burn
80
20
100
Water harvesting and management
Continues cultivation
Use of fertilizers
Farming far away from river banks
70
85
90
40
30
15
10
60
100
100
100
100
Frequent soil movement (levelling)
30
70
100
by Percentages
(%)
60
20
40
No response
(% )
40
80
60
Table 7. Perception of farmers on their adopted agricultural practices
Land use questions: why do
you?
Practice crop rotation?
Allow land to fallowing
Use
organic
manures/compost
Grow leguminous crops to
help replenish soil nutrients
Practice slash and burn
Practice water harvesting
and management
Practice continues cultivation
Use fertilizers
Farm far away from river
banks
Frequently
move
soil
(levelling)
Reasons
assigned
respondents
Reduce pest and disease
Improve soil fertility
Improve soil nutrients
Cannot be grown on land
15
85
Improve soil fertility and
makes seeding easier
To ensure water is available to
crops in dryer periods
Yes, have not enough land for
fallow
To increase yield
To maintain and conserve
water
Easy flow of water
20
80
70
30
85
15
90
40
10
60
30
70
37
4.4 Farmers Nutrient Sources
As the results of this study suggest, the main sources of nutrient available to the majority of the
rice farmers is inorganic fertilizer (Table 8). The heavy dependence on inorganic fertilizers,
according to the farmers, add to their cost of production significantly thereby reducing the rice
production profits. However, a good percentage of the farmers also depend on organic materials
and nitrogen fixing crops for soil fertility improvement. This practice should be encouraged as
they are relatively cheaper for the local farmers to adopt. Besides, they are environmentally
friendly practices (FAO, 2002).
The respondents acknowledge that some of their practices including continuous cropping, slash
and burn and siltation of agricultural water sources are input factors that affect the output
nutrient levels of the soils negatively as suggested by FAO (2002). The positive aspect is that,
fallowing which is a practice some respondents in the study areas provides an external
contribution to soil fertility through the decomposition of the plant residue and undisturbed soil
structure (FAO 2002).
Crops respond differently to different levels of nutrient and water intake. For rice, it studies
suggest that it consumes and require more water than any of the other cereal crops (Westarp,
2002). This means improved conservation practices that enhances nutrient conservation and that
the rainfall pattern and irrigation requirement is critical for rice growing (Westarp, 2002).
Interestingly, the study show that farmers have an understanding of the needed nutrient budget
for rice growing and can relate those need to practices that can either impede or facilitate the
amount of nutrient in the soil. This local knowledge should be a strong basis for building the
capacity of local people in soil conservation practices.
38
Table 8. Farmers’ main sources of fertilizer used in rice production in the study area
Input Nutrients
Output Nutrients
Mineral fertilizers
Local Market
Organic Manure (bio char,
rice straw& brand and
animal droppings)
Biological
N
fixation
(rhizobia)
Sedimentation
Crop
and
residues*
%
Respondents
(Yes)
90
animal 40
%
respondents
(No)
10
60
Nitrogen fixing crops#
15
85
Erosion
60
40
Fallow period
Nutrient build up
30
Ensuring about 5% water Rainwater, river and 40
retention in the paddy field
stream sources
70
60
*Examples include leguminous crops like bambara beans, sorghum. 30% said the plant biomass found on the land during land
preparation is incorporated into the soil as the only source of organic matter
# Sources include bio char, rice straw& brand and animal droppings
4.5 Impact of intensification practices on Soil fertility Status
Fertility levels of the intensified and non-intensified fields were different (Table 10) but they fall
within the regional average (Table 9). This mean that although AI affects the soil fertility levels
in a negative way than the non-intensified practices, the fertility levels of the soils over the years
has been relatively steady without AI depleting the soils beyond the regional status. Howevere,
differences exist in fertility levels among the districts. Organic matter for instance was low in the
Atwma Mponua (1.39%) and Asante Akim (1.43%) districts than the regional average for AI and
NI fields. Potassium (K) was very low in Adansi south and Atwima Mponua (Table 10), with
Asante Akim showing higher levels of the K.
Respondents indicated that the fields they considered as NI fields were fields left to fallow for a
five year period or more. As such the NPK minimal variance noticed in the results for NI and AI
could be strongly linked to the soil composition of the study areas, the water management
practices and general agricultural practices. There were significant level of intensification as
claim by the farmers and their approach to managing the soils was allowing the land to fallow if
they had other land to cultivate on.
39
According to the FAO 2002, when the soil is continuously cultivated without practicing
techniques that would restore the soil, sustainable cropping is not being practiced. Thus when
soil nutrients are removed without replacement, it is considered as a major part of soil
degradation. In reference to the data in Table 9, there levels of fertility are generally low and this
evidence is supported, as suggested by the farmers, low yields of their rice produce. These results
suggest that more soil conservation practices are needed to improve the soil nutrient status within
rice farmers’ fields in the study areas.
Table 9. Fertility Status of soils in the Ashanti region covering also the study
Soil Type
Soil pH
%Organic
Matter
1.5-3.0
%Available
Phosphorus(mg/kg
soil)
0.12-12
% Total Available
Nitrogen
Calcium
(mg/kg soil)
0.12-12
50-100
OffinsoEjura
Kwadaso,
Juaso,
Obuasi
5.3-7.8
4.3-7.0
1.5-3.0
0.12-12
0.1-12
Soil analysis was conducted at Soil Research Institute - CSIR, Kumasi
50-100
40
Table 10. Soil fertility status of Intensified (AI) and Non Intensified (NI) fields of the study area
Districts
Ashanti
Atwima
Mponua
in
Adansi South
Asante Akim
Ahafo
North
Ano
Types of Fields
Ph1:1
SubPlots
1
Components
H2o
%
Organic
Carbon
% Total
% Organic
Others
Nitrogen
Matter
Ca
Mg
K
Na
AI
5.61
2.11
0.21
3.64
3.74
1.87
0.09
0.08
2
NI
6.11
1.87
0.20
3.22
3.47
0.54
0.07
0.08
2
AI
6.52
1.39
0.18
2.40
1.87
0.27
0.02
0.01
1
NI
6.28
1.55
0.19
2.67
3.20
1.34
0.03
0.02
1
AI
5.00
2.67
0.24
4.60
2.54
1.47
0.09
0.06
2
NI
4.80
3.79
0.32
6.53
4.01
3.20
0.21
0.17
2
AI
4.67
2.00
0.21
3.45
3.74
2.14
0.09
0.11
1
NI
4.44
1.92
0.21
3.31
2.67
1.34
0.05
0.06
1
AI
5.60
1.82
0.20
3.14
5.07
2.94
0.18
0.08
2
NI
5.02
2.46
0.23
4.24
6.14
2.67
0.19
0.11
2
AI
4.87
2.69
0.23
4.64
5.34
1.87
0.20
0.11
1
NI
5.73
1.42
0.18
2.45
3.47
2.14
0.11
0.06
1
AI
5.49
2.46
0.22
4.24
8.01
3.74
0.06
0.04
2
AI
5.62
2.08
0.21
3.59
7.74
3.74
0.03
0.02
2
NI
5.20
2.06
0.21
3.55
4.01
2.40
0.14
0.08
1
NI
5.15
1.68
0.20
2.90
2.67
2.40
0.06
0.06
4.6 Challenges of Intensive Farming in study areas
Of the 200 respondents, 190 of them representing 95% of the total respondents indicated they are
facing some challenges in their practice of AI (Figure 4). High labor cost, low yields and high
cost of inputs were the major challenges they attributed to agricultural intensification (AI). These
are common challenges facing many rural farmers (Dbowen, 2012). This, added to the low levels
of soil fertility, compounded their production challenges, thus making their yields to be low.
Agriculture water resource depletion came as another challenge as a result of the practice. Fields
that are highly intensified can have its water resource depleted as suggested by Ruthenberg
(1980). Although the study areas are endowed with abundant water resources, very intensified
41
fields coupled with bad agricultural practices in areas have drastically degraded the rice fuelds
and made rice farming less profitable.
Figure 4. Challenges of agricultural intensification practices in the study area
42
5. CONCLUSION AND RECOMMENDATION
a. About 82% of the rice farmers in the study area were males with the rest being female.
Their monthly income from their farming activities are relatively low when production
costs are factored into the calculation of farmers profits. Only 1% of the farmers earned
GHc 2000 or more per month.
b. Fertility levels were affected by the intensified practices. However, the depletion levels
fell within the regional range.
c. Continuous cropping, slash and burn and siltation of agricultural water sources are input
factors that affect the output nutrient levels of the soils. Fallowing is seen by farmers as
one of the ways to contribute externally to soil fertility improvement through the
decomposition of the plant residue and undisturbed soil structure.
d. High labor cost, low yields and high cost of inputs were some of the major challenges
famers attributed to agricultural intensification (AI).
Recommendations
Based the above findings and discussions, the study recommends the following;
a. Government should help to subsidies cost of rice farming inputs for rice farmers to be
able to make rice production more economically sustainable.
b. Farmers should be encouraged and supported to build upon their skill in soil conservation
techniques such are composting, using of nitrogen fixing crops etc. to help improve the
soil fertility levels of their fields for better yields. This should include capacity building
in water management in valley farming that are practice by most farmers.
43
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47
APPENDIX
Appendix 1 Questionnaire
UNIVERSITY OF EASTERN FINLAND
MSc. in Bio-Economy and Natural Resource Management
Questionnaire for a Study on the Impact of Agricultural Intensification on Soil Fertility and
Biodiversity in Agro Ecosystem: Qualitative and Quantitative Reasoning
District…………………………………………………………………………….
Community…………………………………………………………………………
Date…………………………………………..Time of recording……………………
A. BIO DATA
1. Name of Respondent……………………………………………………………..
2. Age of Respondent: a.> 18 b. 18- 25
3. Sex:
a. [Male]
4. Marital status
a. Single
c. 25-35
b.
b. Married
5. No. of household dependents a. 0-5
d.35-45 e. over 45
[Female]
c. others
b. 5-10.
C. <10.
6. No. of children………..……………………………………….
7. Occupation ………………………………………………………
8. Home town……………………………………………………………….
9. Main crop cultivated a. rice
Others
b. cocoa
10. Average monthly income of the household
c. vegetables d. other cereals e.
48
a. GH¢ 500-1000 b.GH¢ 1000-1500 c. GH¢1500-2000 d. more than GH¢2000
11. Average monthly expenditure of the household
a. GH¢ 500-1000 b.GH¢ 1000-1500 c. GH¢1500-2000 d. more than GH¢2000
12. Educational Level
a. Tertiary
b. SHS/Middle Level c. JHS/Level d. Primary e. No formal
Education
13. What areas are household incomes expended on?
a. Health care
d. Others
b. Education c. Food
d. shelter
e. Social events
14. Years of farming experience
a. 1-5 years
b. 5-10 years c. 10-15 years d. >15 years
15. Other source of income other than agriculture
a. Trading b. Labor
c. Government work d. others…………………..
B. AGRICULTURAL INTENSIFICATION CHARACTERISTICS
16. What crops do you cultivate?
a. Rice b. maize
c. cocoa
d. plantain e. others…………
17. Why do you cultivate these crops?
a. Experience
b. easy to cultivate
income e. Others …………..
c. technology availability d. yields and
18. How many times do you cultivate your land in a year
a. 1
b. 2 times
c. 3 times
d. 4 times
19. How many years has the land been cultivated?
a. 1-5years
b. 5-10years
c. 10-15 years d. >15years
49
20. How is your land preparation processes?
a. Clearing and burning of vegetation b. Ploughing
others………..
c. use of weedicide d.
21. How many acres of land are you cultivating?
a. 1-4acres
b. 4-8acres
c. 8-12 acres d. more
22. Land tenure statues
a. Family b. purchase
c. hired/leased
d. others
23. If purchased or rented, how much?
………………………………………………………………………………
24. Source of labour for farm works
a. Family
b. hired
c. communal d. others…………………..
25. Cost of labour per man/day?
…………………………………………………………………………………..
26. What inputs do you use in your cultivation process?
a. Seed b. herbicides/pesticides
c. fertilizer
d. labor e. others………..
27. How many liters of herbicides / ha do you use
a. 1.1 lit/ha
b. 2lit/ha
c.3-4 lit/ac d. <4 lit/ ha
28. Types of farming tools used in farming?
a. Cutlass
b. hoes
c. tractors/power tillers d. seeders
29. How many times do you apply fertilizer to your crop?
a. 1
b. 2
c. 3
d. 4
e. more
30. Why this frequency?
e. others…….
50
a. Poor fertility b. want higher yield c. improve soil composition
d. subsidies
31. What quantity of fertilizer in kg or bags do you apply per acre? (Specify crop).
………………………………………………………………………..
32. Do you use organic manure/compost and weed plough back?
a. Yes
b. No
33. If Yes why? .................................................................................................
34. Do you allow the land to fallow?
a. Yes
b. No
35. If yes and No why?
…………………………………………………………………………….
36. Do you remove all standing trees before cultivation?
a. Yes b. No
37. Why clear the vegetation?
………………………………………………………………………….
38. What are the likely impacts of the vegetation cover removal?
a. Bare land b. drought and less rain c. heat
d. loss of biodiversity e. others……..
39. Do you think increased fertilization leads to yield increase?
a. Yes
b. no
40. Why continuous cultivation on the same piece of land?
a. Has one parcel of land
b. good yield c. only source of income d. high
fertility
e. other reasons………………………………………..
41. Does your use of chemicals and fertilizer pollute the water sources and farm lands?
a. Yes
b. No
51
42. Activity and presence of some soil organism and insect pest in the field
[Yes (√) No (X)]
Microbial and Insect Activity Frequent Seen in a Long while
Soil burrowing
Easy decomposition
Movement of insect
pest/worms/crickets others
Presence of visible soil
organisms
Piercing and sacking of
leafs/plants
Loose soils
Higher organic matter
Higher water retention
capacity
Darker soils
Not there at all
52
43. What other observations do you see with soil organisms and insect pest in your
field?
……………………………………………………………………………………….
……………………………………………………………………………………….
C. ECONOMIC ASPECTS OF INTENSIFICATION
44.
Crop
Yield/ha (season)
Price (GHc)
Rice (kg/bags)
Maize
Plantain
Cocoa
Vegetables
45. Inputs Usage and their cost on an acre
Inputs
Seed (kg)
Fertilizer (kg)
Rates/Quantity
Frequency
Area (ha)
Cost
53
Chemical
(liters/bottles)
Tools
Land rent
Nets
Others
46. What is the total cost of labor per season per acre?
……………………………………………………………………………………….
47. Do you use farming records for your expenditure and income activities
a. Yes
b. No
48. Are these agricultural practices practiced or not, and why?
Agricultural Practices
Yes
Crop rotation
Fallowing
Use of organic manures/compost
Zero tillage
Growing of leguminous crops
Less use of chemicals
Deforestation
No slash and burn
Water harvesting and
management
Continues cultivation
No use of organic
No
Not
Necessar
Good y
Why
54
matter/fertilizers
Cutting of vegetation (tress
shrubs and grasses)
Farming close to river banks
Over application of chemicals
and inorganic fertilizers
No fallowing
Frequent soil movement
(leveling)
D. TREE RESOURCES AVAILABILITY
49. What trees of socio- economic values are currently available on you farm? List in
order of importance
…………………………………………………………………………………………
…………………………………………………………………………………………
50. How many trees can be found per acre? ………………….
51. What trees were available prior to your farming activities
……………………………………………………………….
52. How many trees were found per acre then? …………………………
53. What is your assessment of trees species loss from your farm land?
a. 0-10% lost b. 10-20% lost c. 20-30% d. 40-50% e. 50-60% f. >60% g. Others
Thank you